Effects of emotional prosody on auditory extinction for voices in patients with spatial neglect

The response of attention systems to emotional stimuli has been intensively investigated in the visual modality. Several findings suggest that neural mechanisms influencing selective attention towards emotional stimuli involve brain systems that are partly independent of cortical networks associated with the control of voluntary attention. To test this hypothesis in the auditory modality, we used a dichotic-listening paradigm in six right-hemisphere patients with left spatial neglect syndrome and left ear extinction during bilateral auditory stimulation. Three different meaningless emotional prosodic utterances (anger, fear, and happiness) were presented to the right or left ear, either alone or paired with another neutral utterance on the other side. Results showed fewer misses for emotional relative to neutral stimuli presented to the left ear, for all emotion categories, including happiness. In addition, we also examined the correlation between the site of brain lesions and the performance of patients for reporting left-ear stimuli. This exploratory anatomical analysis suggested that the relative advantage for emotional over neutral voices may be modulated by the site and extent of brain damage. This modulation consists of reduced influences of emotional prosody in patients with lesions in right ventral prefrontal lobe or right superior temporal cortex. Taken together, our results have provided new evidence that emotional attention mechanisms may be triggered in the auditory modality by negative and positive vocal stimuli.